Text to speech and other similar functions use the url https://api.nexmo.com/tts where as call uses https://rest.nexmo.com/call but both of the operations are defined in the same file with a name url https://rest.nexmo.com which would work with call but not with TTS and tts-prompt.
Text to speech and other similar functions use the url https://api.nexmo.com/tts where as call uses https://rest.nexmo.com/call but both of the operations are defined in the same file with a name url https://rest.nexmo.com which would work with call but not with TTS and tts-prompt.